This invention relates to an apparatus for extracting water from the environmental air and treating it for human use, in particular to produce purified potable water.
An apparatus of the above kind normally draws a stream of moisture-laden air from the environment via an air filtering system mechanically removing therefrom contaminants and dust, and passes it through a moisture collecting system, where the air is cooled below its dew point, whereby liquid from the air is recovered.
The moisture collecting system normally comprises a compressor, evaporation coils with dew-forming surfaces and condensation coils. The compressor is operated to pass a refrigerant liquid through an expander valve to expand it to a gas in evaporation coils, absorbing heat from incoming air, thereby lowering the temperature of the air and causing the condensation of moisture from the air on the dew-forming surfaces of the evaporation coils. The refrigerant gas is then compressed and discharged into the condensation coils where it is cooled by the air and liquefied, to be further recycled in the moisture collecting system.
In addition to collecting moisture from the air, the apparatus of the kind to which the present invention refers normally performs different water treatment operations such as water cooling, filtration and sterilization and, optionally, water heating for the provision of hot water. Both the collection and treatment of water are most often controlled by electrical control means.
From the constructional point of view, an apparatus of the above kind typically comprises a housing having an air inlet with an air filter, an air outlet and an air blower for drawing air into the housing through the air inlet and pushing it out of the housing through the air outlet; a moisture collecting system having dew-forming surfaces and disposed so that the air drawn into the housing passes therethrough and moisture from the air condenses as water on the dew-forming surfaces; a water reservoir receiving water from a moisture collecting system, a pump for the withdrawal of water from the reservoir; a water filtration and sterilization system; and a water dispensing valve, all the components being in suitable fluid communication with each other.
Apparatuses of the above kind are disclosed, for example, in European Pat. No. 597 715, and U.S. Pat. No. 5,259,203. U.S. Pat. No. 5,701,749 and U.S. Pat. No. 5,845,504, the latter patents disclosing systems which, in addition to the water treatment processes mentioned above, may optionally perform water circulation whereby water withdrawn from the reservoir is returned thereto.
It is the object of the present invention to provide a new apparatus for extracting potable water from the environmental air.
In accordance with the present invention there is provided an apparatus for extracting potable water from the environmental air comprising:
a housing having an air inlet with an air filter, an air outlet and an air blower for drawing air into the housing through the air inlet and pushing it out of the housing through the air outlet;
a moisture collecting system having dew-forming surfaces and disposed so that the air drawn into the housing passes therethrough and moisture from the air condenses in the dew-forming surfaces;
a water reservoir capable of receiving water collected as moisture in said moisture collecting system and having a bottom and a side surface constituting a surface of revolution around a longitudinal axis of the reservoir, the reservoir having an outlet port formed at the bottom thereof along said longitudinal axis, for the withdrawal of water from said reservoir, and a circulation inlet port formed in said side surface, said circulation inlet port being designed so as to enable the introduction of water into the reservoir tangentially to said side surface;
a water circulation line extending from said outlet port to said inlet port of the water reservoir through a water filtration and sterilization system to provide the circulation of water through said reservoir by means of a pumping device;
a water dispensing valve for the external dispensing of water therethrough from the circulation water line.
Preferably, the reservoir has an upper section with a cylindrical side surface and a lower section with a conical side surface tapering towards said outlet port, and said circulation inlet port is formed adjacent said lower section.
The apparatus of the present invention provides for continuous circulation of water from the outlet of the water reservoir through the filtration and sterilization system to the circulation inlet port of the reservoir, and through the lower section thereof back to the outlet. The manner of water circulation through the water reservoir and the specific design of its lower portion provide for the swirling vortex-like flow of the water in the reservoir, whereby the stagnation of water and accumulation of sedimentation, as well as the freezing of water in the lower section of the reservoir, are effectively prevented.
Furthermore, due to the circulation arrangement of the present invention, most of the water collected in the water reservoir undergoes multiple circulation through the circulation line and, consequently, through the filtration and sterilization system, which leads to its superior purification.
Preferably, the water reservoir is provided with upper and lower water level sensors. The lower sensor is adapted to indicate the minimal level of water in the reservoir at which the delivery of water through the water dispensing valve may be started and the upper sensor is adapted to indicate the level of water in the reservoir at which further collection of moisture in the moisture collecting system should be terminated. The lower sensor is preferably located above the inlet port of the water reservoir.
Preferably, the apparatus of the present invention further comprises a water chiller system for cooling water in the lower section of the water reservoir. The water chiller system preferably comprises a chiller compressor and evaporation and condensation chiller coils, the evaporation chiller coils being located at the lower section of the reservoir to maintain the water therein cold. The chiller compressor may be a separate condenser or rather it may be the compressor of the moisture collecting system.
Preferably, to produce hot water, the apparatus of the present invention further comprises a water heater in the form of a food-type water tank having an insulating jacket, and a hot-water dispensing valve.